Some devices use a panel loudspeaker to generate sound. A panel loudspeaker is a speaker that creates sound by causing a panel to vibrate. A panel loudspeaker may use a distributed mode actuator (“DMA”), e.g., a piezoelectric transducer, to cause the panel to vibrate and generate sound instead of a voice coil actuator. For instance, a smartphone may include a DMA that applies force to a display panel (e.g., a LCD or an OLED panel) in the smartphone. The force creates vibrations of the display panel that couple to surrounding air to generate sound waves, e.g., in the range of 20 Hz to 20 kHz which may be audible to a human ear.